Resting State Networks in Individuals with and without Reading Disorders

Abstract

Objective: Reading is a complex behaviour requiring the connectivity of numerous brain regions. Resting state functional magnetic resonance imaging (rsfMRI) has recently been used to examine the differences in reading networks in skilled adult readers and skilled and impaired child readers. Such work has shown that the inferior frontal gyrus is a critical region for reading whereby this region shows differences in connectivity to other brain regions between impaired and skilled child readers, and acts as a hub in skilled adult readers. In the current study, rsfMRI was used to examine the neural connectivity of the print-to-speech network and to assess the brain-behaviour relationships that exist within this network in both skilled and impaired adult readers. Method: Brain imaging data (i.e., rsfMRI) and behavioural data (i.e., Tests of Word Reading Efficiency) was collected for individuals with (N = 11) and without (N = 7) reading impairments. Hypothesis: The print-to-speech network in impaired adult readers will show reduced connections to the supramarginal gyrus and to the inferior temporal gyrus, when compared to skilled readers. Additionally, brain-behaviour relationships are anticipated between activity in the inferior frontal gyrus and real word reading scores and between supramarginal gyrus activity and nonword reading scores for both groups. Results: Impaired adult readers showed reduced connectivity between the supramarginal gyrus and the precentral gyrus, and between the inferior temporal gyrus and inferior frontal gyrus, when the supramarginal gyrus and inferior temporal gyrus were selected as seed regions, respectively. Additionally, there were no significant relationships between neural activity and behavioural reading scores. Conclusion: These results support the print-to-speech model, as they demonstrated the connectivity between all regions of interest as defined by the model. Additionally, these results help to strengthen the model by showing that the connectivity within the reading network differs between impaired and skilled readers.